In this thoroughly researched, beautifully written, and intensely moving book, Daniel Sharfstein tracks the experiences of many generations of three families originally classified as "black" as they found new identities across the color line. His massive research, which combines a tireless and ingenious search for sources and sensitive interviews of living subjects, is almost invisible, thanks to prose that combines the lawyerly virtues of clarity and precision with the literary ones of sympathy and grace. The people in this book become almost palpable as they navigate the treacherous waters of racial identity. So does an important historical fact. The color line was never simply a matter of black and white; it was a legal and social construction that accommodated the informal perceptions of color that neighbors and associates acted on every day. Whatever the law in the books, courts were often reluctant to change the racial status of persons who had been acting white or had been treated as white or had white friends and enjoyed high social status. The Invisible Line makes a major breakthrough in the study of the law of race by showing how it was performed in the lives of ordinary people throughout American history.